Air Brake Manual
Air Brake Manual
Air Brake Manual
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On the pre-trip air brake inspection (Section 9), you<br />
must ensure that the parking brake spring is not<br />
manually caged or it will not expand and apply the<br />
brake. The brake chambers should be checked for<br />
cracks and damage. The brake chamber should be<br />
fitted with a dust cap to ensure debris will not enter<br />
the chamber.<br />
During normal service brake operation, the parking<br />
brake spring does not expand. <strong>Air</strong> pressure keeps<br />
the spring caged.<br />
Slack<br />
adjuster<br />
Service <strong>Brake</strong>s Applied<br />
<strong>Brake</strong> On<br />
Service brake<br />
chamber<br />
Mounting Bolts<br />
Clevis and pin<br />
Parking brake<br />
spring<br />
Dust<br />
cap<br />
Push rod<br />
Diaphragm<br />
return<br />
spring<br />
Diaphragm<br />
Spring parking<br />
brake chamber<br />
Using a Spring Parking <strong>Brake</strong><br />
27<br />
12<br />
12<br />
Spring parking brakes (12), added to the brake<br />
chambers of the rear axle on the single unit vehicle,<br />
are illustrated. A control valve (27) is mounted in<br />
the cab.<br />
A supply line of reservoir air is piped from the dry<br />
reservoir to the control valve. Opening the control<br />
valve allows reservoir air pressure to flow to the<br />
spring parking brake chambers, releasing them.<br />
33